Iodido[1-(propan-2-ylidene)thiosemicarbazide-κS]bis(triphenylphosphane-κP)copper(I)

In the mononuclear title complex, [CuI(C4H9N3S)(C18H15P)2], the CuI ion displays a distorted tetrahedral coordination geometry involving two P atoms of two triphenylphosphane molecules, one S atom of a 1-(propan-2-ylidene)thiosemicarbazide molecule and one iodide ion. In the crystal, C—H⋯π interactions [C—H⋯centroid distances = 3.443 (3) and 3.788 (3) Å] and N—H⋯S hydrogen bonds form layers parallel to (100). An intramolecular N—H⋯I hydrogen bond is also observed.

Financial support from the Center of Excellence for Innovation in Chemistry (PERCH-CIC), Office of the Higher Education Commission, Ministry of Education and Department of Chemistry, Prince of Songkla University, is gratefully acknowledged.

Experimental
Triphenylphosphane (0.28 g, 1.07 mmol) was dissolved in 30 cm 3 of acetone at 338 K and then CuI (0.10 g, 0.53 mmol) was added. The mixture was stirred for 2 h and then thiosemicarbazide (0.05 g, 0.55 mmol) was added and the new reaction mixture was heated under reflux for 5 h where upon the precipitate gradually disappeared. The resulting clear solution was filtered off and left to evaporate at room temperature. The crystalline complex, which was deposited upon standing for several days, was filtered off and dried in vacuo.

Refinement
The H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 with U iso (H) = 1.2 U eq (C) and 0.96 Å with U iso (H) = 1.5 U eq (C) for for H atoms on C(sp 2 ) and C(sp 3 ), respectively. All H atoms bonded to N atoms were located in a difference Fourier map and refined isotropically.

Figure 1
The molecular structure with displacement ellipsoids drawn at the 50% probability level. H atoms are omitted for clarity.  Part of the crystal structure with N-H···S hydrogen bonds and C-H···centroid interactions are linked into one dimensional chain shown as dashed lines.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.